Fast recovery from exhaustive endurance exercise can be determinant for sports performance in events incorporating rounds in close time proximity. Protein ingestion increases skeletal muscle protein synthesis and may accelerate recovery (1). The aim of this study was to test the effect of protein ingestion post-exhaustive exercise on skeletal muscle response, metabolic markers and subsequent exercise performance. In a double-blind crossover design, 9 trained male cyclists/triathletes (Age 27.6(Mean) ± 5.5(SD) y-, Maximal Oxygen Consumption (VO2max) 58.1 ± 5.11 ml/kg/min) completed two experimental trials incorporating time to exhaustion cycling exercise at 70% VO2max and assigned to a carbohydrate (CHO, 1.2 g/h) or carbohydrate + protein (CHO+PROT, 0.8 + 0.4 g/h) drink group for 2 h during a 5 h recovery period. After recovery, physical performance was evaluated with time to exhaustion at 70%VO2max. Skeletal muscle samples were obtained at rest, post-exhaustion, post-recovery and post-performance test. Venous blood samples were obtained at rest, during recovery and post-performance test. Exercise to exhaustion time was equal in both trials. CHO+PROT increased cycling performance test by 19.5% (p<0.009) compared to CHO, from 46±17 to 55±21 min (n=5). Respiratory measurements, heart rate and rate of perceived exertion were not different between groups during exhaustive exercise or performance test. Blood glucose was higher during recovery in CHO in some time-points (p<0.05) but insulin peaked at a higher value in CHO+PROT (330 vs 283 pmol/L) at 2.5 h recovery (p<0.05) and no differences were observed between groups during recovery or performance test for blood lactate. Muscle glycogen was equal in both treatments: decreased (p<0.001) from 454±90 to 118±92 mmol/kg DM, returning to 278±73 mmol/kg DM after recovery and decreasing to 137±93 mmol/kg DM after the performance test. Glycogen synthase activity showed no differences between groups and remained elevated in both groups at all time-points post-exhaustion compared to rest (p<0.001). Intracellular muscle signalling showed no main effects of treatment for p-AktSer473, p-AS160Ser588, p-TSC2Thr1462, p-GSKSer21, p-p70S6KThr421/Ser424 and p-p70S6KThr389, p-GSSer641. There was a time-effect for p-AktSer473, p-AS160Ser588 and p-GSSer641 showing a change (increase and decrease, respectively) in phosphorylation at all time-points post exercise compared to rest (p<0.05). In conclusion, CHO+PROT drink during recovery from exhaustive exercise increased subsequent performance, but most metabolic markers in response to exercise and during recovery remained equal between groups. The metabolic effects of protein ingestion during recovery for endurance exercise performance remain largely unexplained.